This invention relates to electrical components and, more particularly, to self-contained or boxless electrical wiring devices, such as switches and receptacles, which may be operatively coupled to an electrical cable and installed without the use of an outlet box.
Electrical components, particularly wiring devices such as switches and receptacles, may be produced in a variety of forms. Often, these components are secured within an outlet box that is mounted within an aperture of a wall of a building or a mobile home. More recently, the self-contained or boxless form of wiring device is being utilized in mobile homes and prefabricated buildings since this form of wiring device does not employ an outlet box and can, therefore, be mounted within a confined space too small to accommodate an outlet box.
One such self-contained wiring device, including both the receptacle form and the switch form, is shown in the U.S. Pat. No. 3,860,319 which issued in the name of Slater on Jan. 14, 1975. Details on the construction of electric terminals for such wiring devices are shown in the U.S. Pat. No. 3,860,739 which issued in the name of Kloth et al. on Jan. 14, 1975. A description of the mechanism and electric contacts for a switch appears in the British Patent No. 940,278 which was published in the name of Lowe et al. on Oct. 30, 1963. The mounting of such wiring devices by means of pawls within an aperture in a wall is disclosed in the U.S. Pat. No. 3,957,336 which issued in the name of Bromberg on May 18, 1976.
The physical structure of the foregoing electrical components is generally complex with the metal terminals and contacts, and their supporting structures of moldable plastic material, having intricate shapes. The unitary enclosure, referred to as the body of the component, including the internal terminal support and wire guiding structure, is generally formed by a molding operation. The terminals and contacts are generally formed by stamping and bending operations, and are then inserted within the supporting structures of the body to complete the assembly of the component.
A problem arises in that the foregoing intricate shapes of the various parts of the self-contained receptables and switches have precluded a direct procedure for their mechanical design with the result that much experimentation is required to produce a self-contained wiring device that can be assembled efficiently. Thus, it is desirable to form the body and its interior supporting structures in a shape that is readily molded without the wastage of excess material and without the need for side draws. In addition, it is desirable to form the body with slots and similar physical features which permit the attachment of both metal and nonmetal components, such as mounting plates, electric terminals, and decorative panels which have corresponding physical features, without the need for excessive fastening devices such as screws and rivets.
A further problem arises in that in the structuring of the wiring device for a facile assembly, the structure of the device should accommodate a mounting feature, such as a pawl assembly, which permits the mounting of the wiring device adjacent a wall stud. In addition, it is desirable to incorporate a single structural member, such as a cover plate, which can be used interchangeably for both switches and receptacles, and thereby reduce the number of different parts required for the assembly of self-contained wiring devices. With respect to the cover plate, it is noted that such a plate should be configured for easy removal to permit attachment of electric cable to the internal terminals, and should readily accommodate cables at one or both ends of the wiring device. While presently available wiring devices may have one or more of the foregoing features, it appears that their configurations do not permit the stimultaneous presence of all of these features. As a result, inconveniences are experienced during the manufacturing and/or the installation process.
Accordingly, it is an object of the present invention to provide new and improved self-contained wiring devices including either an electrical switch mechanism or an electrical outlet receptacle. It is also an object of the invention to provide self-contained wiring devices made from moldable parts for relatively simple and low cost fabrication.
It is another object of the invention to provide new and improved self-contained wiring devices having mounting means which permit quick and easy mounting within a wall opening, without the use of nails or other like fasteners. Such mounting means may also be adapted to permit attachment within the wall opening even when the body of the device abuts a support stud for the wall
It is a further object of the invention to provide new and improved self-contained wiring devices utilizing a snap-fit back cover which has the same construction for receptacles as for switches. The back cover is also capable of universal attachment--i.e., it can be rotated 180.degree. and still fit the device body. Furthermore, the back cover is adapted to be securely attached to the body, yet can be relatively easily disengaged when desired, and facilitates good contact between the cable conductors and the electrical terminals.
It is still another object of the invention to provide new and improved self-contained wiring devices which can easily be adapted to conform to virtually any desired wiring arrangement. The invention also contemplates new and improved contact/terminal structures which interfit with the wiring device body to minimize the amount of metal required to fabricate the contacts. For switch mechanisms, the device provides a new and improved switch wherein the contact members are closed in a wiping action and the switch actuator cannot be disabled by pressure applied directly to the front of device.